Problem: $ { \left[\begin{array}{r}{3} \\ {4} \\ {-1}\end{array}\right]-\left[\begin{array}{r}{-1} \\ {1} \\ {-2}\end{array}\right] = {?} } $
To find the difference of two matrices, subtract the corresponding items between each matrix. ${\left[\begin{array}{r}{3}-{-1} \\ {4}-{1} \\ {-1}-{-2}\end{array}\right]}$ Now, simplify: ${\left[\begin{array}{r}{4} \\ {3} \\ {1}\end{array}\right]}$